1. Field of the Invention
This invention relates to lifting jacks and more particularly to bumper jacks used with automobiles and trucks.
2. Summary of the Prior Art
Bumper jacks have been on the market for many years and are typically in the form of a ratchet bar and a load lifting housing mounted on the ratchet bar for movement therealong. This load lifting housing usually includes a generally C-shaped or J-shaped load support generally conforming to the contour of a bumper.
A typical bumper jack of the prior type is described in Lucker, U.S. Pat. No. 2,783,903, issued May 1, 1956. One of the main concerns of the auto industry today is safety and a bumper jack, if used without brakes or transmission restraints or on sloping road shoulders, can be a very unstable and dangerous lifting device. Some modern bumper jacks have a lifting finger that fits into a slot provided in a vehicle bumper. Such finger arrangements are also shown in the above patent in FIGS. 5 and 6.
While these fingers were certainly of some value in preventing the jack from simply slipping away from the bumper under load conditions, the jack still remained rather unsafe in that it continued to have poor stability in the fore and aft directions as well as rather poor lateral stability on sloping surfaces.
It is the object of the present invention to provide a new form of load engaging device for bumper jacks which will provide a high degree of safety in all directions, including when the jack is used on sloping ground.